Question:medium
Which pair of ions among the following can be separated by precipitation method?
Which pair of ions among the following can be separated by precipitation method?
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Key Points:
Precipitation separation relies on solubility differences. Large solubility differences often exist between ions of different charges (oxidation states), e.g., Ln(II) vs Ln(III).
Ln(II) sulfates (like EuSO$_4$, YbSO$_4$) are often less soluble than Ln(III) sulfates.
Ln(III) ions adjacent in the series (like Gd$^{3+$, Dy$^{3+$) have very similar properties and are hard to separate by precipitation.
Stability of oxidation states is crucial: Eu$^{2+$ and Yb$^{2+$ are relatively stable; Gd$^{2+$ is not.
Precipitation separation relies on solubility differences. Large solubility differences often exist between ions of different charges (oxidation states), e.g., Ln(II) vs Ln(III).
Ln(II) sulfates (like EuSO$_4$, YbSO$_4$) are often less soluble than Ln(III) sulfates.
Ln(III) ions adjacent in the series (like Gd$^{3+$, Dy$^{3+$) have very similar properties and are hard to separate by precipitation.
Stability of oxidation states is crucial: Eu$^{2+$ and Yb$^{2+$ are relatively stable; Gd$^{2+$ is not.
Updated On: Nov 28, 2025
- Eu(II) and Dy(III)
- Gd(III) and Dy(III)
- Eu(II) and Yb(II)
- Eu(II) and Gd(II)